The present invention relates to semiconductor device fabrication and integrated circuits and, more specifically, to field-effect transistor structures for a laterally-diffused metal-oxide-semiconductor (LDMOS) device and methods of forming a LDMOS device.
Device structures for a field-effect transistor generally include a source, a drain, and a gate electrode configured to switch carrier flow in a channel formed between the source and drain during operation. When a control voltage exceeding a designated threshold voltage is applied to the gate electrode, carrier flow occurs in the channel to produce a device output current.
A fin-type field-effect transistor (FinFET) is a non-planar device structure that may be more densely packed in an integrated circuit than planar field-effect transistors. A FinFET may include a fin, a source and a drain formed in sections of the fin, and a gate electrode that wraps about a channel located in the fin body between the source and the drain. The arrangement between the gate structure and fin body improves control over the channel and reduces the leakage current when the FinFET is in its ‘Off’ state in comparison with planar transistors. This, in turn, enables the use of lower threshold voltages than in planar transistors, and results in improved performance and lowered power consumption.
High-voltage integrated circuits used, for example, in microwave/RF power amplifiers typically require specialized circuit technology capable of withstanding higher voltages. Laterally-diffused metal oxide semiconductor (LDMOS) devices are designed to handle higher voltages than logic field-effect transistors and may include features such as a an extended drain.
Improved field-effect transistor structures for a LDMOS device and methods of forming a LDMOS device are needed.